Subcutaneous sensor inserter and method

ABSTRACT

An inserter assembly for continuous glucose monitoring with medication delivery capability where the assembly has a deployment button containing a needle deployment mechanism having a sharp held in a pre-release position, a housing body in which the deployment button is movably received within a top end of the housing body, the housing body having a sensor deployment assembly containing a lumen and a sensor disposed within the lumen and extending out of the lumen to a circuit board that is part of the sensor deployment assembly, the sensor deployment assembly matingly connected to the sharp where the sharp extends beyond the sensor deployment assembly and contains the sensor not fixedly attached to the sharp, and a sensor housing releasably received within a lower end of the housing body, the sharp extending into a sensor deployment assembly recess within the sensor housing and directly above a sensor opening in a bottom of the sensor housing.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to glucose monitoring sensors.More particularly, the present invention relates to glucose monitoringsensors and an inserter assembly therefor for continuous glucosemonitoring in a patient.

2. Description of the Prior Art

Lancets are well-known devices commonly used in the medical field tomake small punctures in a patient's skin in order to obtain samples ofblood. They are utilized in hospitals, other medical facilities, and byprivate individuals such as diabetics for testing droplets of blood forvarious analytes. Typically, lancets are used only once in order toreduce the risk of HIV, hepatitis and other blood-borne diseases. Thelancet or sharp of these devices is driven into the patient's skin by asmall spring that is cocked by a technician or user prior to use. Thelancet is covered with a protective, safety cap that keeps the end ofthe lancet sterile and is removed before use.

A variety of lancet devices are available for use by patients and/orhealthcare practitioners. One lancet device is configured for multipleand/or repeated uses. In this variety, the user typically pushes abutton or other device on a lancet injector to cause a lancet topenetrate the skin of a patient. More commonly, the lancet deviceeffectively encases and fires the lancet into the patient's skin inorder to puncture in an accurate, standardized and consistent manner.The lancet injector may also be provided with an adaptor cap to controland adjust the depth of penetration of the needle of the lancet.

Integrated lancet and sensor devices have been developed that combinethe lancet and test strip or sensor into a single package. Theseintegrated devices are typically used with a lancet injector where theintegrated lancet and test strip is removed from the lancet injector andconnected to a meter after acquisition by the test strip of the bloodsample produced by the lancet, or used with a meter with built-in lancetinjector.

More recently, continuous glucose monitoring devices have been developedfor implanting into a patient's skin. Continuous monitoring systemstypically use a tiny implantable sensor that is inserted under the skin,or into the subcutaneous fat layer to check analyte levels in the tissuefluid. A transmitter sends information about the analyte levels by wayof, for example, a wire to a monitor or wirelessly by radio waves fromthe sensor to a wireless monitor. These devices are typically implantedfor three to seven days of use to monitor in real-time a patient'sglucose level.

One such device is disclosed in U.S. Pat. No. 5,299,571 to JohnMastrototaro. The device is an apparatus for implantation of in-vivosensors. The apparatus includes a housing, a dual-lumen tube extendingtherefrom, and an in-vivo sensor received within one of the lumens ofthe tube. A needle is received within the other lumen of the tube, andis used to insert the tube through the skin. After implantation, theneedle is removed, and the flexible tube and sensor remain beneath theskin.

U.S. Patent Application Publication 2010/0022863 (2010, Mogensen et al.)discloses an inserter for a transcutaneous sensor. The inserter includesa needle unit and a sensor housing. The needle unit includes a needlehub and a carrier body. The sensor housing and the needle hub arereleasably connected and when they are connected, the insertion needleis placed along the sensor (e.g. surrounding the sensor wholly orpartly). The carrier body guides the movement relative to the housingbetween a retracted and an advanced position. When released, the needleunit and the sensor housing are forced by a spring unit to an advancedposition where the needle and sensor are placed subcutaneously.Upwardly-bent parts on the leg of the housing set the insertion angle ofabout 30° into the skin of the patient.

U.S. Patent Application Publication 2012/0226122 (2012, Meuniot et al.)discloses an inserter device for an analyte sensor. The device includesa housing that is positioned above the subcutaneous fat layer, a bladeshuttle, and a sensor shuttle. A spring is compressed between the bladeshuttle and the sensor shuttle. The blade shuttle and sensor shuttlemove towards the subcutaneous fat layer. When a spring force is releasedby the spring, the blade shuttle moves towards and pierces into thesubcutaneous fat layer creating a pathway into the subcutaneous fatlayer. The analyte sensor is implanted by the sensor shuttle byfollowing the blade shuttle into the pathway created by the bladeshuttle. The blade shuttle is then retracted from the subcutaneous fatlayer, leaving the analyte sensor in the fat layer.

U.S. Patent Application Publication 2013/0256289 (2013, Hardvary et al.)discloses a diagnostic device. The diagnostic device has partiallyretractable hollow guide needles for the intradermal placement ofdiagnostic elements fixedly connected to measuring means within thisdevice. This obviates the need to remove the guide needle and to connectthe diagnostic elements to the measuring means after placement into theskin.

SUMMARY OF THE INVENTION

Continuous glucose monitoring (CGM) devices have been slow to be adoptedby many patients due to the pain and long term discomfort of initialdeployment and long term use (3 to 7 days). Currently available devicesare commonly compared and criticized on CGM user forums for their painof deployment.

Pain of deployment can be shown to be directly related to the design ofthe device. Axons that pass through the subcutaneous layer and end inthe epidermis are called nociceptors. These specialized neurons transmitpain messages. The density of these pain receptors ranges between 2 and2500 neurites/mm² just below the skin surface, and varies greatlydepending on location. The probability and magnitude of a pain responseduring any incision is proportional to the number of affectednociceptors and the trauma inflicted upon these nociceptors. Withnociceptors located throughout the thickness of the epidermis, a deeperincision is more likely to trigger a pain response due to the increasedlikelihood of trauma to more nociceptors.

When inserted into subcutaneous tissue, the combined cross sectionalarea of a sensor and introducer is proportional to the force ofinsertion and also to the probability and magnitude of triggering painresponse. FIG. 1 is a graph 10 showing the maximum peak force 12 ofinsertion (lbs.) of various commercial inserter sets plotted against themeasured cross section area 14 of the inserter set (in²×10⁻⁴). As can beseen by a linear regression of the data points in FIG. 1, the peak forceincreases linearly with cross sectional area with a regression line 16represented by equations 1 and 1a, which have an R² value of 0.932. Datain graph 10 is for needles inserted at 90 degrees to the skin surfaceregardless of the intended insertion angle of the particular needle.peak force (lb_(f))=(0.3998)(cross sectional area (in²))+0.0556lb_(f)  (1)peak force (N)=(0.0223)(cross-sectional area (m²))+1.100 N  (1a)

Among the tested needles for graph 10 in FIG. 1 and graph 20 in FIG. 2,Brand A is a 22 gauge split needle with a lumen, Brand B is a 22-24gauge needle with a bi-lumen, Brand C is a 23-24 gauge split needle witha single lumen, and Brand D is a 26 gauge needle. A split needle meansthat about a third of the needle is removed for a distance creating askive cut in the needle. The Brand A needle with lumen has the highestpeak force. The Brand C needle has a peak force that is slightly lessthan the larger 22 gauge Brand A split needle. The Brand D needle is aneedle intended for insertion at 45 degrees to the skin surface. It isnotable that the peak force increases by 11% when inserting a needle at45 degrees compared to 90 degrees to the skin surface. Thus, when usedas intended, the peak force for Brand D needle would be 11% greater thanas shown in FIG. 1.

It is important to note that the sensor of the present invention wasinstalled in various needle sizes and also tested for peak insertionforce. As can be seen from the graph, the sensor of the presentinvention in a 22 gauge split needle has a lower peak insertion forcethan the comparable Brand C needle. Also, the sensor of the presentinvention in a 24 gauge split needle had a lower peak insertion forcethan the Brand D 26 gauge needle notwithstanding having a largercross-sectional area than the Brand D needle. The needle with the lowestpeak force (FIG. 1) and lowest work (FIG. 2) is the sensor of thepresent invention in a 27 gauge XTW Skive Cut needle with an ovalcross-sectional shape.

The cross sectional area of an inserter set (i.e. needle and sensor)also strongly correlates with the relative intensity of pain ofinsertion as reported by users of these devices. The Brand D device isconsidered by users as being much more comfortable than the earlierBrand A system. The present invention the same or a larger needle gaugehas a better (lower) peak insertion force of a comparable brand needleas seen from FIGS. 1 and 2.

FIG. 2 is a graph 20 showing work 22 (lb-in) plotted against thecombined cross sectional area 24 (in²×10⁻⁴) of the sensor and introducerof various commercial introducer sets. For insertion of a sensor andintroducer in combination, the length or depth of insertion intosubcutaneous tissue is proportional to the work energy (force timesdistance) and also proportional to the probability and magnitude oftriggering pain response from the user. As can be seen by a linearregression of the data points of FIG. 2, the work increases linearlywith cross sectional area with a regression line 26 represented byequations 2 and 2a, which have an R² value of 0.9715.Work (lb-in)=(0.0439)(cross sectional area (in²))+0.0133  (2)Work (N-m)=(6.23E−5)(cross-sectional area (m²))+1.50E−3 N-m  (2a)

FIG. 3 is a graph 30 with typical force of insertion 32 (lbs.) plottedagainst insertion distance 34 (in) to demonstrate the concept of workenergy. FIG. 3 is a plot of data obtained from three separate insertionforce measurements for a Brand R inserter with a Brand R sensor. As thesharp penetrates tissue, the force is dynamically recorded. The integralof a curve 36 (i.e., the area 38 under one of curves 36 a-36 c) is thework energy (lb-in). Work energy (force times distance) is proportionalto the incidence of triggering a pain response by users of the inserter.In simple terms, small, shallow incisions hurt less for the reasonsstated above. Therefore, an inserter that reduces or minimizes insertionpain is more likely to be adopted by patients.

Reducing or minimizing insertion pain is one criterion for patientacceptance of any continuous monitoring system. Other criteria includethe convenience and ease-of-use of the inserter device. Therefore, aneed exists for an inserter set and an inserter assembly that reduces orminimizes the patient's pain and inconvenience of inserting a continuousmonitoring sensor. The present invention achieves these and otherobjectives by providing a continuous analyte monitoring inserterapparatus for subcutaneous placement of a sensor into a patient and asharp/needle that minimizes insertion pain with a reducedcross-sectional area.

In one embodiment of the present invention, a sharp useful forcontinuous glucose monitoring has an elongated tubular body with apointed tip. The elongated tubular body has a generally oval orelliptical cross-sectional shape and defines a conduit therethrough. Asharp open region extends a predefined distance from the pointed tipalong the elongated tubular body and has a portion of the generally ovaltubular body removed, thereby defining an unenclosed concave well withinthe remaining elongated tubular body. In another embodiment, the sharpincludes a continuous monitoring sensor retained in the concave well,where the top surface of the continuous monitoring sensor residescompletely within the concave well formed by the wall of the tubularbody.

Another aspect of the present invention is an inserter assembly. In oneembodiment, the inserter assembly is a single action inserter assemblyadapted to substantially simultaneously using a single action performthe steps of (1) implanting the sensor subcutaneously into the patient,(2) fixedly seating a sensor deployment assembly that includes thesensor within a sensor housing attached to the patient, (3) retracting aneedle used to implant the sensor, and (4) releasing the inserterassembly from the sensor housing. In one embodiment, the action ofretracting the needle is performed by retracting the needle into theinserter assembly. In another embodiment, the inserter assembly furtherincludes implanting a lumen along with the sensor subcutaneously in thepatient.

In another embodiment, the inserter assembly includes a deploymentbutton containing a needle deployment mechanism. The needle deploymentmechanism has a needle carrier incorporating a sharp and a needlecarrier catch that temporarily prevents the needle carrier from moving.The deployment button is movably received in a housing body, where thehousing body has a sensor deployment assembly that connects in matingagreement to the sharp. The sharp extends beyond the sensor deploymentassembly into the sensor housing and contains the sensor, which is notfixedly attached to the sharp. A sensor housing is releasably receivedwithin the housing body.

In another embodiment, the inserter assembly includes a housing bodyhaving a first body end and a second body end. A deployment button is atleast partially disposed in and slidable within the housing body throughthe first body end, where the deployment button is movable between afirst position and a second position. The second position may be alocked position. A deployment mechanism slidably disposed within thedeployment button is movable between a ready position, an insertionposition, and a retracted position. The deployment mechanism has aneedle.

A sensor deployment assembly is disposed within the housing body andremovably mated with the deployment mechanism. The sensor deploymentassembly has a needle bore in which the needle is disposed when thedeployment mechanism is in the ready position. A sensor is partiallydisposed within the needle or the needle bore, where the deploymentmechanism, the needle, and the sensor define a deployment axis. Thesensor has an electrode system and an electrical contact portion. In oneembodiment, the electrical contact portion is parallel to but spacedfrom the deployment axis. In another embodiment, the electrical contactportion extends transversely away from the deployment axis. In oneembodiment, for example, the electrical contact portion extendssubstantially perpendicularly from the deployment axis.

The inserter assembly also includes a sensor housing disposed at andremovably retained by the second body end of the housing body. Thesensor housing has a bottom surface that defines a sensor openingtherethrough and aligned with the deployment axis.

Movement of the deployment button from the first position to the secondposition causes the sensor to be implanted subcutaneously into thepatient along the deployment axis, the needle of the deploymentmechanism to retract to the retracted position, the sensor deploymentassembly to be fixed within the sensor housing, and inserter assembly torelease from the sensor housing. In one embodiment, the inserterassembly includes the housing body, the deployment button and thedeployment mechanism.

In some embodiments, the movement of the deployment button from thefirst position to the second position is a single movement causingsubstantially at the same time the sensor to be implanted subcutaneouslyinto the patient along the deployment axis, the needle of the deploymentmechanism to retract to the retracted position, the sensor deploymentassembly to be fixed within the sensor housing, and the housing body,the deployment button and the deployment mechanism to release from thesensor housing.

In one embodiment, the single activation has an auditory indication thatthe sensor is implanted in the patient and the inserter assembly isreleased from the sensor housing. In another embodiment, the singleactivation has a sensory indication through the inserter assembly thatthe sensor is implanted in the patient and the inserter assembly isreleased from the sensor housing.

In another embodiment, the housing body has a body recess for receivingand retaining a button catch when the deployment button is in the secondposition.

In another embodiment, the housing body has a body catch retaining thesensor housing partially within the housing body. The body catch isreleased from the sensor housing by the deployment button when thedeployment button is oriented in the second position.

In another embodiment, the inserter assembly further includes a lumendisposed on the needle, where the inserter assembly substantiallysimultaneously implants the lumen with the sensor subcutaneously intothe patient

In another embodiment, the sensor deployment assembly includes a sensordeployment body, a sensor deployment guide, and a sensor carrier. Thesensor deployment body has a sensor deployment locking mechanismconfigured to engage the sensor housing when the button is moved to thesecond locked position, thereby locking the sensor deployment assemblywith the sensor housing. In one embodiment, the sensor deploymentlocking mechanism is one or more resilient deployment catches on thesensor deployment assembly biased to engage a deployment catch surfaceon the sensor housing. Similarly, the deployment locking mechanism maybe one or more resilient deployment catches on the sensor housing thatare biased to engage respective deployment catch surfaces on the sensordeployment assembly.

The sensor deployment guide is attached to the sensor deployment bodyand positioned to stop travel of the deployment assembly when thedeployment button is moved to the second locked position. For example,the deployment guide comes in contact with the sensor housing to stoptravel of the deployment assembly. The sensor carrier is attached to thesensor deployment guide, secures the sensor, and has a board-receivingface. The sensor carrier also defines a sensor bore extendingtransversely from and in communication with the needle bore. The sensorextends through the sensor bore and along the board-receiving face. Inone embodiment, the board-receiving face is substantially parallel tobut spaced apart from the deployment axis, where the sensor bends overthe sensor carrier. In other embodiments, the board-receiving face is ontop surface of the sensor carrier.

In some embodiments, the sensor deployment assembly further includes asensor board with electronic coupling pads electrically coupled to theelectrical contact portion of the sensor. The sensor board mates withthe board-receiving face and in electrical communication with theelectrical contact portion of the sensor. The electronic coupling padsare positioned to be electrically coupled to measuring electronics.

In another embodiment, the board-receiving face is on a top sensorcarrier surface and extends transversely to the deployment axis. In suchan embodiment, a sensor board mates with the board-receiving face andhas electronic coupling pads positioned to electrically couple tomeasuring electronics. The sensor extends through the sensor bore andalong the sensor board with the electrical contact portion of the sensorelectrically coupled to the electronic coupling pads.

In some embodiments, the sensor carrier defines a sensor groove alongthe top sensor carrier surface, where the sensor extends through thesensor groove on its way to the board-receiving face or sensor board.

In some embodiments, the deployment axis is substantially perpendicularto the bottom surface of the sensor housing, where the bottom surface ofthe sensor housing is configured to contact the patient duringimplantation of the sensor.

In some embodiments, the inserter assembly includes a lumen with aportion of the lumen sealingly fixed to the sensor deployment assemblyand extending through the needle opening to a lower lumen end. In someembodiments, the lumen is a single lumen tube sized to receive theneedle and the sensor therein, where the electrode system on the sensorextends from the lower lumen end of the single lumen tube. In someembodiments, a working electrode of the electrode system is spaced fromthe lower lumen end of the single lumen tube by about 4 mm to about 7mm. In other embodiments, the working electrode is spaced from the lowerlumen end by about 2 mm to about 10 mm.

In other embodiments, the lumen is a dual lumen tube defining a firstlumen tube for receiving the needle therethrough and a second lumen tubefor receiving the sensor. The second lumen tube defines a second lumenside opening adjacent an upper lumen end and in communication with theneedle bore. The second lumen tube also defines one or more second lumenelectrode opening adjacent the lower lumen end to expose an electrodesystem on the sensor to a sample to be measured. In some embodiments, itis contemplated that the needle may be a solid needle; in otherembodiments, the needle defines a passageway therethrough. Accessiblethrough the second lumen side opening, the working electrode of theelectrode system in some embodiments is spaced from the lower lumen endof the single lumen tube by about 4 mm to about 7 mm. In otherembodiments, the working electrode is spaced from the lower lumen end ofthe single lumen tube by about 2 mm to about 10 mm.

In other embodiments, the inserter assembly includes a sealing cover orcover assembly that is releasably attachable to a top of the sensordeployment assembly. The sealing cover includes resilient sensor housingengagement tabs, where each has a tab catch configured to be receivedwithin a corresponding engagement tab receiver in the sensor housing tolock the sealing cover to the sensor housing. The sealing cover also hasa sealing member on a bottom surface that aligns with and seals into theneedle bore.

In some embodiments, the sealing cover defines a delivery bore with afirst bore end and a second bore end at a delivery bore opening througha bottom surface of the sealing cover. In some embodiments, the sealingcover includes a flexible medication delivery tube connected to thefirst bore end of the delivery bore.

In yet other embodiments, the inserter assembly includes an electricalcomponent housing that is releasably attachable to the sensor housingand configured to receive and transmit electrical signals generated bythe electrode system on the sensor.

In other embodiments, the inserter assembly includes a cover assemblythat is releasably attachable to a top of the sensor deploymentassembly. The cover assembly has a sensor housing engagement mechanismconfigured to engage the sensor housing to lock the cover assembly tothe sensor housing. A sealing member on a bottom surface of the coverassembly aligns with and forms a seal between the delivery bore and theneedle bore. A sensor board with electronic coupling pads iselectrically coupled to the electrical contact portion of the sensor,where the sensor board mates with the board-receiving face with theelectronic coupling pads positioned for being electrically coupled tomeasuring electronics. The cover assembly also includes an electricalcomponent configured to receive and transmit electrical signalsgenerated by the electrode system on the sensor. The electricalcomponent has electrical contacts coupled to the electronic couplingpads on the sensor board.

In other embodiments, the inserter assembly includes a resilient buttoncatch on the housing body or the sensor housing, where the button catchis biased to engage a button catch surface on the other of the housingbody or the sensor housing when the deployment button is in the secondposition. The inserter assembly may also include a resilientneedle-carrier catch on the deployment button or the needle carrier,where the needle-carrier catch is biased to disengage a second catchsurface on the other of the deployment button or the needle carrier whenthe deployment button is moved to the second position. The inserterassembly may also include a resilient housing catch on the housing bodyor the sensor housing, where the housing catch is biased to disengage ahousing catch surface on the other of the housing body or the sensorhousing when the button in moved to the second position.

In another aspect of the invention, a method of inserting an in-vivoanalyte sensor subcutaneously for continuous analyte monitoring of apatient includes the steps of providing a single action inserterassembly having a needle, an implantable sensor, a deployment button forimplanting the implantable sensor using the needle and for retractingthe needle, and a sensor housing for retaining the implanted sensor inan implanted orientation once deployed by the deployment button; andusing a single action to activate the deployment button of the singleaction inserter assembly that causes the following actions tosubstantially simultaneously occur: (1) implanting the sensorsubcutaneously into the patient, (2) fixedly seating the sensor withinthe sensor housing attached to the patient, (3) retracting the needleinto the inserter assembly, and (4) releasing the inserter assembly fromthe sensor housing.

In another embodiment of the method, the providing step includesproviding a single action inserter assembly that has a lumen disposed onthe needle and the using step includes implanting the lumensubcutaneously into the patient with the sensor and fixedly seating thelumen within the sensor housing attached to the patient.

In another aspect of the present invention, a continuous analytemonitoring inserter apparatus for subcutaneous placement of a sensorinto skin of a patient minimizes pain to a patient. In one embodiment,the apparatus has a single action inserter assembly having a housingbody with a first body end and a second body end. A deployment button ispartially disposed in and slidable within the housing body through thefirst body end, where the deployment button being movable between afirst position and a second position. A sensor housing is partiallydisposed within and removably retained in the second body end. A needleis movably disposed within the single action inserter assembly. Theneedle has a cross-sectional shape that minimizes a peak force ofinsertion into the skin of the patient. An implantable sensor ispartially disposed within the needle. The inserter assembly is adaptedto substantially simultaneously implant the sensor subcutaneously intothe patient, retract the needle, fix the sensor within the sensorhousing and release the inserter assembly from the sensor housing with asingle activation of the deployment button caused by moving thedeployment button from the first position to the second position whileminimizing pain to the patient.

In another embodiment, a longitudinal portion of the needle has a skivecut along a length of the needle from a sharp end of the needle to apredefined location.

In another embodiment, the needle is oriented substantiallyperpendicular to a surface of the single action inserter, where thesurface is a portion of the sensor housing and intended for placementagainst the skin of the patient.

In another embodiment, the needle has a cross-sectional shape of anoval, an ellipse, an egg-shape, or an oblong shape. In anotherembodiment, the longitudinal portion of the needle has a cross-sectionalshape of an oval, an ellipse, an egg-shape, or an oblong shape.

In another aspect of the present invention is a method of minimizingpain when inserting an in-vivo analyte sensor subcutaneously forcontinuous analyte monitoring of a patient. In one embodiment, themethod includes providing a single action inserter assembly having aneedle with a cross-sectional shape that minimizes a peak force ofinsertion into the skin of the patient, an implantable sensor, adeployment button for implanting the implantable sensor using the needleand for retracting the needle, and a sensor housing for retaining theimplanted sensor in an implanted orientation once deployed by thedeployment button; and using a single action to activate the deploymentbutton of the single action inserter assembly that causes the followingactions to substantially simultaneously occur: (1) implanting the sensorsubcutaneously into the patient, (2) fixedly seating the sensor withinthe sensor housing attached to the patient, (3) retracting the needleused to implant the sensor into the inserter assembly, and (4) releasingthe inserter assembly from the sensor housing, wherein the needle andthe single action minimizes pain when inserting the sensorsubcutaneously.

In another embodiment of the method, the providing step includesproviding a needle with a skive cut along a longitudinal portion of theneedle from a sharp end of the needle to a predefined location along thelength of the needle.

In another embodiment of the method, the providing step includesproviding a needle that is oriented substantially perpendicular to asurface of the single action inserter, where the surface is a portion ofthe sensor housing and intended for placement against the skin of thepatient.

In another embodiment of the method, the providing step includesproviding a needle with an oval, elliptical, egg-shaped, or oblongcross-sectional shape. In another embodiment of the method, theproviding step includes providing a needle with the longitudinal portionhaving an oval, elliptical, egg-shaped, or oblong cross-sectional shape.

In another aspect of the present invention, a method of making a sharpincludes providing a longitudinal tubular body having a first end and asecond end; compressing the longitudinal tubular body to have asubstantially oval and/or elliptical cross-sectional shape; removing aportion of the tubular body proximate the first end and extending apredefined distance towards the second end where the portion is parallelto a major axis of the oval/elliptical cross-sectional shape; andforming a sharp tip on the first end.

In yet another aspect of the present invention, a method of continuousanalyte monitoring includes placing an inserter assembly on an insertionsite of a patient. The inserter assembly has a sensor carrier, aninserter set with a sharp and an analyte sensor, and a deploymentassembly. The deployment assembly includes a deployment button, ahousing body, and a deployment mechanism. The method also includes thesteps of pressing the deployment button of the introducer set, therebydeploying the introducer set into subcutaneous tissue of the patient;retracting the deployment assembly and removing the sharp from thepatient while leaving the analyte sensor deployed in the sensor carrierand in the patient; and removing the deployment assembly from the sensorcarrier.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing insertion force data for various commercialinserter sets of the prior art, where maximum peak force of insertion isplotted against the measured cross sectional area of the inserter set.

FIG. 2 is a graph showing data for various commercial inserter sets ofthe prior art, where the work of insertion is plotted against themeasured cross sectional area of the inserter set.

FIG. 3 is a graph showing data for one inserter set of the prior art,where insertion force is plotted against the distance of insertion andwhere the area under a curve is the work energy.

FIG. 4 is a perspective view of one embodiment of a sharp of the presentinvention showing the sharp tip, a sharp open region, and a portion ofthe sharp body.

FIG. 5 is an end perspective view of the sharp of FIG. 4 showing theconcave well defined by the sharp open region.

FIG. 5A is a diagram representing the cross-sectional area of the sharpopen region of the sharp of FIG. 5 with a sensor disposed in the concavewell.

FIG. 6 is a perspective view of an inserter set of the present inventionshowing a portion of the sharp of FIG. 4 with a continuous monitoringsensor disposed in the concave well.

FIG. 6A is a side view of a portion of the inserter set of FIG. 6showing the continuous monitoring sensor disposed in the concave well ofthe sharp.

FIG. 7 is an end perspective representation of the inserter set of thepresent invention showing the continuous monitoring sensor disposed inthe concave well.

FIG. 7A is an end representation of an inserter set of the presentinvention showing the shape of the sharp and concave well with acontinuous monitoring sensor disposed in the concave well.

FIG. 8 is a graph showing data for one inserter set of the presentinvention, where insertion force is plotted against the distance ofinsertion and where the area under a curve is the work energy.

FIG. 9 is a perspective view of one embodiment of an inserter assemblyof the present invention showing the top, end, and side surfaces.

FIG. 10 is a side, cross-sectional view of the inserter assembly of FIG.9 as taken along line A-A with the button and deployment mechanism inrespective first or up positions.

FIG. 11 is a side, cross-sectional view of the inserter assembly of FIG.10 shown with the button and deployment mechanism in a second or downposition.

FIG. 12 is a side, cross-sectional view of the inserter assembly of FIG.10 shown with the button in the second position and the deploymentmechanism in a retracted position.

FIG. 13 is a side and top perspective view of one embodiment of a sensorhousing assembly of the present invention.

FIG. 14 is a side, cross-sectional view of the sensor housing assemblyof FIG. 13 as taken along line B-B of FIG. 13.

FIG. 15 is an enlarged perspective view of the sensor carrier withsensor showing the back side of one embodiment of the sensor.

FIG. 16 is an enlarged perspective view of the sensor carrier withsensor showing the front side of the sensor and the proximal end portionof the sensor shown in FIG. 15.

FIGS. 17 and 18 are enlarged front and back perspective views of thesensor shown in FIGS. 15-16, respectively.

FIG. 19 is an enlarged perspective view of the back side of the sensorand sensor board.

FIG. 20 is an enlarged perspective view of the front side of the sensorand sensor board.

FIG. 21 is an enlarged perspective view of the sensor, sensor board andthe electronic component housing.

FIG. 22 is an enlarged side view of the sensor, sensor board and theelectronic component housing shown in FIG. 21.

FIG. 23 is a perspective view of another embodiment of an inserterassembly of the present invention.

FIG. 24 is a sectional view of a sensor carrier with a single lumenconfiguration.

FIG. 24A is an enlarged view of the sensor carrier with the single lumenconfiguration shown in FIG. 24.

FIG. 24B is an enlarged perspective view of another embodiment of asensor carrier with sensor and single lumen showing the back side of thesensor carrier.

FIG. 24C is an enlarged perspective view of the sensor carrier withsensor and single lumen showing the front side of the sensor and theproximal end portion of the sensor shown in FIG. 24B.

FIG. 24D is an enlarged cross-sectional view of the sensor carrier shownin FIG. 24B.

FIG. 24E is a bottom view of the sensor carrier shown in FIG. 24B.

FIG. 25 is a sectional view of a sensor carrier with sensor and a duallumen configuration.

FIG. 25A is an enlarged view of the sensor carrier with the sensor andthe dual lumen configuration shown in FIG. 25.

FIG. 25B is an enlarged perspective view of another embodiment of asensor carrier with sensor and single lumen showing the back side of thesensor carrier.

FIG. 25C is an enlarged perspective view of the sensor carrier withsensor and single lumen showing the front side of the sensor and theproximal end portion of the sensor shown in FIG. 25B.

FIG. 25D is an enlarged cross-sectional view of the sensor carrier shownin FIG. 25B.

FIG. 25E is an enlarged perspective view of the back side of the sensorand sensor board.

FIG. 26 is a perspective view of the sensor housing assembly with thesingle lumen showing a medication delivery assembly for mating to thelumen in the sensor carrier.

FIG. 27 is a side elevation view of the sensor housing assembly of FIG.26.

FIG. 28 is a partially exploded, perspective view of the sensor housingassembly of FIG. 26 with the single lumen and showing the electronicmodule decoupled from the sensor housing.

FIG. 29 is a partially exploded, perspective view of the sensor housingassembly with the single lumen and showing the medication deliveryassembly decoupled from the sensor housing.

FIG. 30 is a sectional, side view of the sensor housing assembly andmedication delivery assembly of FIG. 29.

FIG. 31 is a sectional, side view of the inserter assembly of FIG. 23shown in a pre-insertion position.

FIG. 32 is a sectional, side view of the inserter assembly of FIG. 23shown in an intermediate, sensor inserting position.

FIG. 33 is a sectional, side view of the inserter assembly of FIG. 23shown in a post-insertion position with the needle carrier in aretracted position and immediately prior to separation of the introducerhousing and deployment button from the sensor housing.

FIG. 34 is a perspective view of another embodiment of an inserterassembly of the present invention.

FIG. 35 is a front view of the inserter assembly of FIG. 34.

FIG. 36 is a side, cross-sectional view of the inserter assembly of FIG.34 as taken along line E-E with the button and deployment mechanism inrespective first or up positions.

FIG. 37 is an enlarged, cross-sectional view of the sensor deploymentassembly of FIG. 36.

FIG. 38 is a rear, cross-sectional view of the inserter assembly of FIG.34.

FIG. 39 is a side and top perspective view of another embodiment of asensor housing assembly of the present invention.

FIG. 40 is a side, cross-sectional view of the sensor housing assemblyof FIG. 39 as taken along line D-D of FIG. 39.

FIG. 41 is an exploded, perspective view of the sensor housing assemblyof FIG. 39 showing various components.

FIG. 42 is side and top perspective view of another embodiment of asensor housing assembly of the present invention with a single lumen andshowing a medication delivery assembly separated from the sensor housingassembly.

FIG. 43 is a side and top perspective view of the sensor housingassembly of FIG. 42 showing the electronic cover assembly separated fromthe sensor housing.

FIG. 44 is a side and bottom perspective view of the sensor housingassembly of FIG. 43.

FIG. 45 is an exploded, perspective view of the sensor housing assemblyof FIG. 42 showing various components.

FIG. 46 is an enlarged, perspective view of the electronic circuit boardassembly of the electronic module partially shown in FIG. 45.

FIG. 47 is an enlarged, perspective view of the electronic modulehousing of the electronic module shown in FIG. 45.

FIG. 48 is side and top perspective view of another embodiment of asensor housing assembly of the present invention showing a dual lumenand a medication delivery assembly connected to the sensor housingassembly.

FIG. 49 is an exploded view of the sensor housing assembly of FIG. 48showing various components.

FIG. 50 is a side, cross-sectional view of the sensor housing assemblyof FIG. 48 as taken along line G-G of FIG. 48.

FIG. 51 is an enlarged view of the circled area H of FIG. 50.

FIGS. 52A, 52B and 52C are simplified cross-sectional views of theinserter assembly showing the position of various inserter catches whenthe inserter assembly is in the first/ready position.

FIGS. 53A, 53B, 53C, and 53D are simplified cross-sectional views of theinserter assembly showing the position of various inserter catches whenthe inserter assembly has been activated by a single action performed bya user.

FIG. 54 is a flow chart showing the steps of the process that occurswhen an inserter assembly of the present invention is used to implant ananalyte sensor subcutaneously in a patient.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Exemplary embodiments of the present invention are illustrated in FIGS.4-54. FIGS. 4 and 5 illustrate perspective views of one embodiment of asharp 100 of the present invention. Sharp 100 includes a sharp body 102,a sharp open region 104, and a sharp tip 106. Sharp body 102 is anannular section of sharp 100 that extends longitudinally and defines anenclosed conduit 101 therethrough. In one embodiment, sharp 100 is madefrom 27 gauge XTW stainless tubing having an outside diameter of about0.016 inch (0.41 mm) nominal and an inside diameter of about 0.012 inch(0.30 mm) nominal. The tubing is then flattened to have an oval orelliptical shape with an outside height 108 along the minor axis of theoval or elliptical shape of about 0.0120 inch (0.30 mm).

A wire EDM machining operation is used to remove a portion of the tubingwall 103 along sharp 100 a predefined distance to define sharp openregion 104, thereby reducing the overall height 110 of sharp 100 alongthe minor axis of the oval or elliptical shape at sharp open region 104to about 0.008 inches (0.20 mm). The wire EDM machining operation can beperformed on cylindrical tubing or on flattened, oval tubing asdescribed above. Sharp open region 104 is a section of an annulus thatextends longitudinally with the tubing wall 103 along the length ofsharp open region 104 defining an unenclosed concave well 114 from sharptip 106 to sharp body 102.

Concave well 114 is sized to receive a continuous monitoring sensor 120(shown in FIGS. 6-7). In one embodiment, concave well 114 is sized toreceive a continuous monitoring sensor 120 having a size up to about0.012 (0.30 mm) wide by about 0.004 (0.10 mm) thick. In one embodiment,a continuous monitoring sensor top surface 122 is positioned flush withor below a top surface 116 a of tubing wall 116 along sharp open region104. The incision of such a sharp and sensor combination has a crosssectional area 112 of about 1.33×10⁻³ in² (0.81 mm²), where crosssectional area 112 is defined within outside surface 100 a of tubingwall 103 and top surface 116 a of tubing wall 116 at sharp open region104 (also shown in FIG. 5A). Having continuous monitoring sensor 120disposed in concave well 114 of sharp 100 minimizes the combined crosssectional area of the sharp and sensor as compared to cylindrical sharpsof the same tubing or cylindrical sharps with a sharp open region but acontinuous monitoring sensor that extends out of the sharp open region.As a result, the insertion force for sharp 100 with continuousmonitoring sensor 120 is considerably lower than the insertion force ofprior art insertion sets.

Referring to FIGS. 6 and 7, portions of an embodiment of an inserter set190 of the present invention are shown. Inserter set 190 has acontinuous monitoring sensor 120 disposed in concave well 114 of sharp100. As shown in FIG. 6, continuous monitoring sensor 120 has a workingelectrode 130, a counter electrode 132, and a multi-segmented referenceelectrode 134 along a sensor top surface 122. In one embodiment as shownin FIG. 7, continuous monitoring sensor 120 extends along all or a majorportion of sharp open region 104 from sharp tip 106 to sharp body 102and at least partially into sharp body 102. In one embodiment,continuous monitoring sensor does not occupy sharp tip 106 so as toretain a smooth sloped profile of sharp 100 at tip 106.

FIG. 6A is a side view of part of inserter set 190 with continuousmonitoring sensor 120 disposed in concave well 114 of sharp 100. Sharp100 is constructed so that continuous monitoring sensor 120 is securelyheld in concave well 114 during insertion into skin tissue by frictionalengagement with an inside surface 100 b of tubing wall 103. Optionally,a water-soluble adhesive or other compound (not shown) is appliedbetween continuous monitoring sensor 120 and concave well 114, where thewater-soluble adhesive or other compound dissolves and releasescontinuous monitoring sensor 120 when sharp 100 is deployed into skintissue.

In one embodiment shown in an end view of FIG. 7A, tubing wall 103 alongsharp open region 104 (shown in FIGS. 6A & 7) occupies more than 180° ofthe oval shape. From a vertical line 123 bisecting the oval into rightand left halves 125 a, 125 b, tubing wall 103 extends more than 90°along the elliptical/oval paths away from vertical line 123 on each half125 a, 125 b from a point of intersection 126 between vertical line 123and lower portion 127 of oval. As a result, tubing wall 103 extendsupward and then curves back toward vertical line 123 to define anopening 128 in sharp open section 104 that has a reduced width 129compared to a maximum width 130 of concave well 114. Since tubing wall103 arcs toward vertical line 123, reduced width 129 of opening 128restricts continuous monitoring sensor 120 from exiting through opening128. In one embodiment, sidewalls 124 of continuous monitoring sensor120 frictionally engage an inside surface 100 b of tubing wall 103. Forenhanced frictional engagement, continuous monitoring sensor 120optionally has a cross-sectional shape that substantially matches thatof concave well 114 along one or more sides of continuous monitoringsensor 120. Therefore, continuous monitoring sensor 120 may be installedand removed from sharp 100 by sliding it into or out through sharp tip106 (shown in FIG. 6). After insertion, sharp 100 is removed from thetissue and continuous monitoring sensor 120 remains in the tissue. Thus,sharp 100 can be retracted while continuous monitoring sensor 120remains in the tissue for continuous glucose monitoring.

Referring now to FIG. 8, a plot 80 shows insertion force data forinserter set 190 of the present invention with force of insertion 82plotted vs. the distance 84 of insertion. Each of plotted lines 86 inFIG. 8 represents a separate measurement at a different, nearbyinsertion site. The force of insertion 82 (lb) is plotted against thedistance or depth of insertion 84 (inches). As shown in FIG. 8, theforce of insertion 82 is substantially constant with only modestincreases beyond a depth 84 of about 0.1 inches (2.5 mm), even when theinsertion depth 84 is about 0.3 inches (7.6 mm). By inserting sharp 100in a direction perpendicular to the tissue surface, inserter set 190 candeposit continuous monitoring sensor 120 into the critical subcutaneouslayer with minimal trauma to the tissue. The typical insertion depthduring use is from 4 mm to 7 mm for accurate measurement of subcutaneousglucose. Other inserter designs insert a sharp at angles of about 45degrees (more or less) thus increasing length of insertion by 41%. Workenergy (force times distance; the area under a curve 86) has been shownto be proportional to the incidence of pain response reported by users.

To further reduce or minimize the pain of insertion, sharps 100 of thepresent invention are used in an inserter assembly 200 that deployscontinuous monitoring sensor 120 into skin tissue. Introducer designsthat rely on the patient to drive sharp 100 into the patient's owntissue greatly benefit the patient by providing low-force and low-workdesigns. This benefit derives from psychological reasons as well as fromthe practical aspect of having to insert a sharp into a relatively softabdomen or hip.

Referring now to FIG. 9, a perspective view shows one embodiment of aninserter assembly 200 of the present invention that includes a housingbody 202 and a deployment button 204 slidably received in housing body202. A sensor housing 206 is removably attachable to housing body 202.Housing body 202, sensor housing 206, and deployment button 204 arecollectively referred to herein as a deployment assembly 1000. Adeployment mechanism 208 (shown in FIG. 10) is operable with deploymentbutton 204, housing body 202, and sensor housing 206. Housing body 202includes one or more recesses 212 for engagement with deployment button204 as is discussed in more detail below with reference to FIG. 10.Housing body 202 also includes a locking mechanism 205 (e.g., resilienttab, clip, protrusion, etc.) that engages sensor housing 206 and retainsit together with the inserter assembly 200 forming the deploymentassembly 1000. Locking mechanism 205 is discussed in more detail below.

FIG. 10 shows a side, cross-sectional view of inserter assembly 200taken along line A-A of FIG. 9. Housing body 202 has a first body end213 and a second body end 215 with deployment button 204 at leastpartially disposed in and slidable within housing body 202 through firstbody end 213. Housing body 202 includes at least one first catch surface210 defined by a recess 212, opening, ledge, protrusion, or otherstructure. First catch surface 210 is constructed and sized to engage acorresponding resilient locking catch 214 on deployment button 204 whena user presses deployment button 204 into housing body 202 from a firstor ready position (shown in FIG. 10) to a second or inserted position(shown in FIG. 11). One or more springs 216 (e.g., coil spring) disposedbetween deployment button 204 and housing body 202 bias deploymentbutton 204 towards the first or ready position as shown in FIG. 10. Whendeployment button 204 is in the first (ready position), locking catch214 is held inward in tension by abutment with housing wall 218. Whenthe user presses deployment button 204 down, the tension on lockingcatch 214 causes locking catch 214 to move outward towards its resting,non-tensioned/non-compressed position to engage first catch surface 210.Of course, housing body 202 and deployment button 204 can be configuredso that first catch surface 210 is on deployment button 204 and lockingcatch 214 is on housing body 202. Other releasable locking mechanismsknown in the art are also acceptable. In one embodiment, inserterassembly 200 includes at least two first catch surfaces 210 andcorresponding locking catches 214 as shown in FIG. 10.

Deployment mechanism 208 is slidably received in a deployment mechanismcavity 228 in deployment button 204. A deployment cap 230 closesmechanism cavity 228 and can be removed for access to deploymentmechanism 208. Deployment mechanism 208 includes a deployment spring232, a needle/sharp carrier 234 with a needle carrier catch 235, and asensor deployment assembly 236 with a resilient deployment catch 238.Deployment spring 232 (e.g., a coil spring) is disposed between springsupport component 231 and needle carrier 234 in a tensioned orientation.Needle carrier catch 235 prevents needle carrier 234 from being movedtowards deployment cap 230 by deployment spring 232. When the userpresses deployment button 204, needle carrier catch 235 is released frombutton catch surface 240 by carrier release surface 203 of housing body202 and deployment spring 232 then biases needle carrier 234 towards adeployment cap 230.

Referring now to FIG. 11, a side, cross-sectional view of inserterassembly 200 is shown with deployment button 204 and deploymentmechanism 208 in their respective second positions (needle insertedpositions). When the user presses button 204, deployment mechanism 208moves downward towards sensor housing 206 due to engagement between abutton catch surface 240 and carrier catch 235. At the end of travel fordeployment button 204, a deployment guide 244 abuts a floor 246 or otherstructure of sensor housing 206 to stop the travel of deployment button204 and of deployment mechanism 208. In its second carrier position(inserted position), sensor deployment assembly 236 is positioned withinsensor housing 206 and deployment body catch 238 engages base catchsurface 242. In the second carrier position, the deployed continuousmonitoring sensor 120 is retained by sensor housing 206 and ispositioned for electrical communication with electronic module 300(internal electrical/electronic components not shown for clarity)attached to sensor housing 206. Simultaneously with retention ofcontinuous monitoring sensor 120 in sensor housing 206, carrier catch235 contacts carrier release surface 203. This causes carrier catch 235to move to a second carrier catch orientation as shown by the dashedoutline of carrier catch 235 and to disengage from button catch surface240 with an audible “click” thereby allowing deployment spring 232 toautomatically return carrier assembly 208 to a third carrier position(up position) with sharp 100.

FIG. 12 shows a side, cross-sectional view of inserter assembly 200 withdeployment button 204 in its second position (down position), sensor 120deployed, and deployment mechanism 208 having returned to its thirdcarrier position (up or retracted position). Deployment body catch 238remains engaged with base catch surface 242 to maintain sensordeployment assembly 236 engaged with sensor housing 206. Lockingcatch(es) 214 also remain engaged with first catch surface(s) 210 tomaintain button 204 in its second position. With continuous monitoringsensor 120 now deployed, housing body 202 with deployment button 204 anddeployment mechanism 208 (aka the deployment assembly) may be disengagedfrom sensor housing 206 and removed, leaving sensor housing 206 in placeon the patient for continuous glucose monitoring. It is important tonote that, even though the cross-sectional shape, insertion angle, andsharpness of the insertion needle are aspects of the invention thatreduce the amount of perceived pain experienced by the user uponinsertion, the described single-action feature of the present inventionis another aspect of the invention that also reduces the amount of painthe user perceives upon insertion even when other needles in the priorart are used such as, for example, needles having larger cross-sectionaldiameters and higher insertion peak forces.

Referring now to FIG. 13, a top perspective view shows an embodiment ofsensor housing assembly 800 separate from inserter assembly 200. Alsoshown attached to sensor housing 206 is electronic module 300.Electronic module 300 is removably attachable to sensor housing 206 and,thus, re-usable with other inserter assembly 200. Continuous monitoringsensor 120 is shown in wireframe in order to show the relative positionsof working electrode 130, counter electrode 132, and reference electrode134 since electrodes 130, 132, 134 are on the hidden side of sensor 120in this view. FIG. 14 shows a side cross-sectional view of sensorhousing assembly 800 as taken along line B-B of FIG. 13. Sensordeployment assembly 236 remains with sensor housing 206 due to continuedengagement between deployment body catch 238 and base catch surface 242.Sensor deployment assembly 236 includes a deployment body 236 a,deployment guide 244, a sensor carrier 270, and a sensor board 280.Continuous monitoring sensor 120 extends through a sensor opening 250 inbottom 252 of sensor housing 206 when implanted subcutaneously in apatient. Working electrode 130, counter electrode 132, and referenceelectrode 134 (shown in FIG. 13) are electrically coupled to electricalcomponents (not shown) disposed in or a part of electronic module 300,which electrical components are configured to read, transmit, display,and/or record glucose measurements. Although a glucose sensor isdescribed and used in this embodiment, it is contemplated that otheranalytes may be similarly measured using the present invention and wouldinvolve substituting the glucose sensor with an appropriate analytesensor for the analyte to be measured.

Turning now to FIGS. 15 and 16, there are illustrated enlarged views ofone embodiment of the sensor carrier 270 and sensor 120. Sensor carrier270 has a sensor/needle bore 272 that receives sharp 100 and sensor 120,a sensor anchor space 274 with a sensor wrap bar 275 and sensor groove276 formed in a carrier board-receiving surface 278. As shown, sensor120 wraps around sensor wrap bar 275 in sensor anchor space 274. Sensorproximal portion 120 a, which has a plurality of contact pads 121 forelectrically coupling electrodes 130, 132 and 134 to measuringelectronics, is disposed within sensor groove 276. It is the flexibilityof sensor 120 that permits such an orientation (i.e. wrapping) withoutdamaging the electrical conduits embedded within sensor 120 thatelectrically couple electrodes 130, 132, 134 to contact pads 121. FIGS.17 and 18 illustrate only sensor 120 enlarged to show the bentorientation of sensor 120 when mounted in sensor carrier 270. It iscontemplated that sensor 120 may have a length that is shorter wherewrapping the sensor is not required and, in fact, the looping of thesensor 120 around wrap bar 275 is unnecessary. Sensor 120 could besecured to sensor carrier 270 using other known techniques so long asthe sensor proximal portion 120 a is either disposed within sensorgroove 276 or configured to position the plurality of contact pads 121for electrically coupling electrodes 130, 132 and 134 to measuringelectronics.

FIGS. 19 and 20 illustrate enlarged views of sensor 120 and sensor board280. Sensor board 280 has one or more board notches 284 configured toattach to/mate with carrier board-receiving surface 278 of sensorcarrier 270 (See FIG. 16), and a sensor side 281. Sensor side 281includes electrical coupling elements 282 that are electrically coupledto sensor contact pads 121 and therefore to electrodes 130, 132 and 134.Sensor board 280 also has component module housing side 286 with aplurality of electronic coupling pads 288.

FIGS. 21 and 22 illustrate perspective and side views, respectively, ofsensor 120, coupled to sensor board 280 and electronic module 300.Electronic module 300 has at least one module housing arm 304 forremovable attachment to mating receptacles in sensor housing 206.Extending from an electrical coupling side 306 is a plurality ofelectrical coupling elements 308 that align and electrically couple withthe plurality of electronic coupling pads 288 of sensor board 280.Electronic module 300 contains all of the electrical components requiredto enable sensor 120 to work as well as to provide the means forreading, transmitting, displaying, and/or recording glucose and/or otheranalyte measurements.

In one embodiment, sensor housing 206 has a very compact form factormeasuring 1.5 inches (7.1 mm) long by 1.0 (25.4 mm) wide by 0.3 (7.6 mm)high that is very small and convenient to the patient.

Continuous Monitoring System with Lumen

FIG. 23 illustrates another embodiment of an inserter assembly 200′ fora continuous monitoring system. Like the embodiment shown in FIG. 9, aninserter assembly 200′ includes a housing body 202, a deployment button204 slidably received in housing body 202, and a sensor housing 206′that is removably attachable to housing body 202. As previouslydisclosed, housing body 202, sensor housing 206′, and deployment button204 are collectively referred to herein as a deployment assembly 1000.Housing body 202 includes one or more recesses 212′ for engagement withdeployment button 204 and also includes a locking mechanism 205′ (e.g.,resilient tab, clip, protrusion, etc.) that engages sensor housing 206′and retains it together with the deployment assembly 1000. Lockingmechanism 205′ functions in the same way as previously discussed withrespect to inserter assembly 200 except for the position of the lockingmechanism relative to the housing body 202 and deployment button 204.The main difference between the embodiment illustrated in FIG. 23 andthe embodiment in FIG. 9 is the position of recesses 212′ in housingbody 202 and of locking mechanism 205′. Recesses 212′ in FIG. 23 areoffset from a transverse axis of housing body 202, which allows forincorporation of two needle carrier catches 235 (shown in FIGS. 31-33).Locking mechanism 205′ is positioned to latch and hold sensor housing206′ at a housing outside catch surface 206 b whereas locking mechanism205′ is positioned to latch and hold sensor housing 206′ at a housinginside catch surface 206 a. In both embodiments, locking mechanism 205,205′ release sensor housing 206, 206′ (respectively) when the sensor isdeployed. Also shown in FIG. 23 is an adhesive component 600 that isattached to the bottom of the sensor housing 206′ and secures sensorhousing 206′ to the patient upon deployment of the continuous monitoringsystem.

Turning now to FIG. 24, there is illustrated a cross-sectional view ofsensor housing 206′ containing a sensor deployment assembly 236 with alumen 900 and the electronic module 300′. FIG. 24A is an enlarged viewof area M shown in FIG. 24. Sensor deployment assembly 236 remains withsensor housing 206′ due to continued engagement between deployment bodycatch 238 and base catch surface 242. Sensor deployment assembly 236includes a deployment body 236 a, deployment guide 244, a sensor carrier270 a with a single lumen tube 973 fixedly attached to sensor carrier270 a, and a sensor board 280. Continuous monitoring sensor 120 andsingle lumen tube 973 extend through a sensor opening 250 in bottom 252of sensor housing 206′. Sensor opening 250 has a sensor opening grommet251 to center sensor carrier 270 a and provides a moisture resistantseal between sensor opening 250 of sensor housing 206′, lumen tube 973,and sensor carrier 270 a. Grommet 251 is swaged down by the compressionof the elastic material of deployment guide 244 and sensor carrier 270a, thus forming a compression tight seal between sensor opening 250 andsensor housing 206′. Also shown deployed onto sensor deployment assembly236 is a medication delivery assembly 400, which is discussed in greaterdetail below. Working electrode 130, counter electrode 132, andreference electrode 134 of an electrode system 135 (shown in FIG. 24B)are electrically coupled to electrical components (not shown) disposedin or a part of electronic module 300′, which electrical components areconfigured to receive and transmit electrical signals generated byelectrode system 135. Although a glucose sensor is described and used inthis embodiment, it is contemplated that other analytes may be similarlymeasured using the present invention and would involve substituting theglucose sensor with an appropriate analyte sensor for the analyte to bemeasured.

FIGS. 24B and 24C illustrate enlarged views of sensor carrier 270 a andsensor 120. Sensor carrier 270 a has a sensor/needle bore 272, singlelumen 973 that receives sharp 100 (shown in FIGS. 31-32) and sensor 120,and a sensor groove 276 formed in a carrier top 271 a and in carrierboard-receiving surface 278. As shown, sensor 120 bends around sensorcarrier 270 a from a top of needle bore 272 and extends into sensorgroove 276. Sensor proximal portion 120 a, which has a plurality ofcontact pads 121 for electrically coupling electrodes 130, 132 and 134to measuring electronics placed within electronic module 300′, isdisposed within sensor groove 276. It is the flexibility of sensor 120that permits such an orientation (i.e. bending) without damaging theelectrical conduits embedded within sensor 120 that electrically coupleelectrodes 130, 132, 134 to contact pads 121. Sensor 120 is secured tosensor carrier 270 a using known techniques so long as the sensorproximal portion 120 a is either disposed within sensor groove 276 orconfigured to position the plurality of contact pads 121 forelectrically coupling electrodes 130, 132 and 134 to measuringelectronics.

FIG. 24D illustrates an enlarged cross-sectional view of sensor carrier270 a along line C-C. At a carrier bottom surface 271, there is formed agrommet receiving recess 275 that surrounds a carrier bottom protrusion275 a that extends beyond carrier bottom surface 271 and has needle bore272 therethrough. Grommet receiving recess 275 and carrier bottomprotrusion 275 a have tapered sides to better create amoisture-resistant seal with grommet 251. FIG. 24E illustrates a bottomview of the sensor carrier 270 a showing grommet receiving recess 275 ascircular, but recess 275 may have any other form.

Turning now to FIG. 25, there is illustrated a cross-sectional view ofsensor housing 206′ containing a sensor deployment assembly 236 with adual lumen and the electronic module 300′. FIG. 25A is an enlarged viewof area P shown in FIG. 25. Sensor deployment assembly 236 remains withsensor housing 206′ due to continued engagement between deployment bodycatch 238 and base catch surface 242. Sensor deployment assembly 236includes a deployment body 236 a, deployment guide 244, a sensor carrier270 b with a dual/double lumen tube 974 fixedly attached to sensorcarrier 270 b, and a sensor board 280 a. Continuous monitoring sensor120 and double lumen tube 974 extend through a sensor opening 250 inbottom 252 of sensor housing 206′. Sensor opening 250 has a sensoropening grommet 251 to center sensor carrier 270 b and provides amoisture resistant seal between sensor opening 250 of sensor housing206′, lumen tube 974, and sensor carrier 270 b. Grommet 251 is swageddown by the compression of the elastic material of deployment guide 244and sensor carrier 270 b, thus, forming a compression tight seal betweensensor opening 250 and sensor housing 206′. As can be seen in FIG. 25A,double lumen tube 974 has first lumen tube 974 a for the sharp/needle100 and a second lumen tube 974 b for sensor 120. Second lumen tube 974b has a second lumen side opening 974 g adjacent an upper lumen end 974c that communicates with a sensor bore 276 a that communicates at atransverse angle with needle bore 272 and with sensor groove 276.Adjacent a lower lumen end 974 d are one or more second lumen electrodeopenings 974 h, which expose electrode system 135 (shown in FIG. 24B) onsensor 120 to a sample to be measured. Also shown deployed onto sensordeployment assembly 236 is a medication delivery assembly 400. Workingelectrode 130, counter electrode 132, and reference electrode 134 of anelectrode system 135 (shown in FIGS. 25C and 25E) are electricallycoupled to electrical components (not shown) disposed in or a part ofelectronic module 300′, which electrical components are configured toreceive and transmit electrical signals generated by electrode system135.

FIGS. 25B and 25C illustrate enlarged views of another embodiment ofsensor carrier 270 b and sensor 120. Sensor carrier 270 b has asensor/needle bore 272, dual/double lumen tube 974 that receives sharp100 and sensor 120, and a sensor groove 276 formed in carrier top 271 abut not in carrier board-receiving surface 278. As shown, sensor 120bends around sensor carrier 270 b from needle bore 272 at the junctionof sensor bore 276 a up to sensor groove 276 in carrier top 271 a andacross from and in spaced relationship with carrier board-receivingsurface 278. Sensor proximal portion 120 a has a plurality of contactpads 121 for electrically coupling electrodes 130, 132 and 134 tomeasuring electronics, where contact pads 121 face carrierboard-receiving surface 278. It is the flexibility of sensor 120 thatpermits such an orientation (i.e. bending) without damaging theelectrical conduits embedded within sensor 120 that electrically coupleelectrodes 130, 132, 134 to contact pads 121. Sensor 120 is secured tosensor carrier 270 b using known techniques so long as the sensorproximal portion 120 a is either disposed against sensor board 280 orconfigured to position the plurality of contact pads 121 forelectrically coupling electrodes 130, 132 and 134 to measuringelectronics.

FIG. 25D illustrates an enlarged cross-sectional view of sensor carrier270 b along line C′-C′. At a carrier bottom surface 271, there is formeda grommet receiving recess 275 that surrounds a carrier bottomprotrusion 275 a that extends beyond carrier bottom 271 and has needlebore 272 therethrough. Grommet receiving recess 275 and carrier bottomprotrusion 275 a each have tapered sides to better create amoisture-resistant seal with grommet 251.

FIG. 25E illustrates a rear perspective view of sensor board 280 andsensor 120. Sensor board 280 has one or more board notches 284configured to mate with carrier board-receiving surface 278 of sensorcarrier 270 b. In the dual/double lumen arrangement, sensor board has atop board notch 289 to accommodate the bend of sensor 120 forpositioning sensor proximal end 120 a against an outer sensor side 281 aof sensor board 280 for coupling sensor contact pads 121 of sensor 120to the electrical coupling elements 282 that electrically connect totraces 282 a which, in turn, are electrically coupled to a plurality ofelectronic coupling pads 288. As is evident from the figures, the reasonfor this arrangement of the contact pads 121 of sensor 120 facing theouter sensor side 281 a of sensor board 280 is that the dual lumen 974requires that electrode system 135 face toward the sensor board 280causing the contact pads to face toward the lumen wall; unlike thesingle lumen configuration where the electrode system 135 faces awayfrom sensor board 280. Also in this double lumen embodiment, the middleelectrical coupling pad 288 is offset from the center because of sensorproximal portion 120 a needing to contact the outer sensor side 281 a ofsensor board 280 and because sensor proximal portion would interferewith the electrical contact between middle electrical coupling pad 288and the corresponding electrical contact of the electronic module 300′.

Turning now to FIGS. 26, 27 and 28, there are illustrated perspective,side and expanded views of the sensor housing assembly 800. As seen inFIGS. 26 and 27, sensor housing assembly 800 includes sensor housing206′, electronic module 300′ releasably attached to sensor housing 206′and medication delivery assembly 400 releasably attached to the top ofsensor deployment assembly 236 that is captured within sensor housing206′. In the embodiment illustrated, sensor carrier 270 a (shown in FIG.24) has a single lumen tube 973. FIG. 28 illustrates the difference inhow electronic module 300′ mechanically couples to sensor housing 206′compared to the embodiment shown in FIG. 21. Component housing 300′ hasa top resilient tab 302′ that has a tab catch 302 a that mates with atab catch slot 207 a in a top 207′ of sensor housing 206′ whereascomponent housing 300 illustrated in FIG. 21 has side resilient tabs304.

FIG. 29 illustrates medication delivery assembly 400 decoupled fromsensor housing 206′. Medication delivery assembly 400 has a pair ofresilient sensor housing engagement tabs 402, each with an engagementtab catch structure 404 extending from a respective engagement tab 402.Engagement tab catch structure 404 is received within an engagement tabreceiver 209 in sensor housing 206′. A flexible medication delivery tube406 is connected to medication delivery assembly 400.

Turning now to FIG. 30, there is illustrated a side, sectional,elevation view of the medication delivery assembly 400 shown in FIG. 29.Medication delivery assembly 400 has a delivery bore 408 thatcommunicates on one end with delivery tube 406 and ends at delivery boreopening 408 a in a bottom surface 410 of assembly 400. Delivery boreopening 408 a has a sealing member 412 that aligns with and seals intoneedle bore opening 236 b in a top surface 236 c of deployment body 236a. It is contemplated that a sealing cover 450 (not shown) may be usedto plug needle bore opening 236 b when medication delivery assembly 400is not used or temporarily removed from sensor housing 206′. Sealingcover 450 would have all of the structural features of delivery assembly400 except that there would be no delivery bore 408, delivery tube 408or delivery bore opening 408 a.

FIG. 31 shows a side, cross-sectional, elevation view of inserterassembly 200′. Housing body 202 includes at least one first catchsurface 210 defined by a recess 212′, opening, ledge, protrusion, orother structure. First catch surface 210 is constructed and sized toengage a corresponding resilient locking catch 214 (hidden from view) ondeployment button 204 when a user presses deployment button 204 intohousing body 202 from a first or ready position (shown in FIG. 31) to asecond or inserted position (shown in FIG. 32). One or more springs 216(e.g., coil spring) disposed between deployment button 204 and housingbody 202 bias deployment button 204 towards the first or ready positionas shown in FIG. 31. When deployment button 204 is in the first (readyposition), locking catch 214 (hidden from view) is held inward intension by abutment with housing wall 218 (more clearly shown in thefirst embodiment in FIG. 10). When the user presses deployment button204 down, the tension on locking catch 214 causes locking catch 214 tomove outward towards its resting, non-tensioned position to engage firstcatch surface 210 when locking catch aligns with recess 212′. Of courseas previously disclosed, housing body 202 and deployment button 204 canbe configured so that first catch surface 210 is on deployment button204 and locking catch 214 is on housing body 202. Other releasablelocking mechanisms known in the art are also acceptable. In oneembodiment, inserter assembly 200′ includes at least two first catchsurfaces 210 and corresponding locking catches 214.

Deployment mechanism 208 is slidably received in a deployment mechanismcavity 228 in deployment button 204. A deployment cap 230 closesmechanism cavity 228 and can be removed for access to deploymentmechanism 208. Deployment mechanism 208 includes a deployment spring232, a needle/sharp carrier 234 with a needle carrier catch 235 and asharp/needle 100, and a sensor deployment assembly 236 with a resilientdeployment catch 238. Deployment spring 232 (e.g., a coil spring) isdisposed and supported by a spring support component 231 on one end andconnected to needle carrier 234 on an opposite end. Spring supportcomponent 231 is integrally formed with deployment button 204 or fixedlyattached to deployment button 204 within deployment mechanism cavity228. Spring support component 231 retains deployment spring 232 withindeployment button 204. Deployment spring 232 is disposed between springsupport component 231 and needle carrier 234 in a tensioned/compressiveorientation. Needle carrier catch 235 prevents needle carrier 234 frombeing moved within deployment mechanism cavity 228 towards a deploymentcap 230 by deployment spring 232. When the user presses deploymentbutton 204, needle carrier catch 235 is released by carrier releasesurface 203 of housing body 202 and deployment spring 232 then biasesneedle carrier 234 towards deployment cap 230 thereby movingneedle/sharp 100 out of the way after having inserted lumen 973, 974 andsensor 120 subcutaneously in the patient.

Referring now to FIG. 32, a side, cross-sectional view of inserterassembly 200′ is shown with deployment button 204 and deploymentmechanism 208 in their respective second positions (needle insertedpositions). When the user presses button 204, deployment mechanism 208moves downward towards sensor housing 206′ due to engagement between abutton catch surface 240 and carrier catch 235. At the end of travel fordeployment button 204, a deployment guide 244 abuts a floor 246 or otherstructure of sensor housing 206′ to stop the travel of deployment button204 and of deployment mechanism 208. In its second carrier position(inserted position), sensor deployment assembly 236 is positioned andretained within sensor housing 206′ because deployment body catch 238engages base catch surface 242. In the second carrier position, thedeployed continuous monitoring sensor 120 and lumen 973 of sensordeployment assembly 236 are retained by sensor housing 206′ and sensor120 is positioned for electrical communication with electronic module300′ (internal electrical/electronic components not shown for clarity)attached to sensor housing 206′. Simultaneously with retention ofcontinuous monitoring sensor 120 in sensor housing 206′, carrier catch235 contacts carrier release surface 203. This causes carrier catch 235to move to a second carrier catch orientation as shown by the dashedoutline of carrier catch 235 a and to disengage from button catchsurface 240 with an audible “click” thereby allowing deployment spring232 to automatically return carrier assembly 208 to a third carrierposition (up position) with sharp 100.

FIG. 33 shows a side, cross-sectional view of inserter assembly 200′ ina post sensor deployment position with deployment button 204 in itssecond position (down position), sensor 120 and lumen 973 deployed, anddeployment mechanism 208 having returned to its third carrier position(up position). Deployment body catch 238 remains engaged with base catchsurface 242 to maintain sensor deployment assembly 236 engaged withsensor housing 206′. Locking catch(es) 214 also remain engaged withfirst catch surface(s) 210 to maintain button 204 in its secondposition. With continuous monitoring sensor 120 now deployed, housingbody 202 with deployment button 204 and deployment mechanism 208 (akathe deployment assembly) may be disengaged from sensor housing 206′ andremoved, leaving sensor housing 206′ in place on the patient forcontinuous glucose monitoring and automatic insulin delivery.

In one embodiment, sensor housing 206′ has a very compact form factormeasuring 1.5 inches (7.1 mm) long by 1.0 (25.4 mm) wide by 0.3 (7.6 mm)high that is very small and convenient to the patient.

Continuous Monitoring System with Top-Mounted Electronics Module

FIG. 34 illustrates another embodiment of an inserter assembly 200″ fora continuous monitoring system. Like the embodiments shown in FIG. 9 andFIG. 23, an inserter assembly 200″ includes a housing body 202, adeployment button 204 slidably received in housing body 202, and asensor housing 206″ that is removably attachable to housing body 202. Aspreviously disclosed, housing body 202, sensor housing 206″, anddeployment button 204 are collectively referred to herein as adeployment assembly 1000. Housing body 202 includes one or more recesses212′ for engagement with deployment button 204 and also includes alocking mechanism 205′ (e.g., resilient tab, clip, protrusion, etc.)that engages housing outside catch surface 206 b on sensor housing 206′and retains it together with the deployment assembly. Locking mechanism205′ functions in the same way as previously discussed with respect toinserter assembly 200′ and disengages from sensor housing 206″ when thesensor 120 is deployed. Optionally, sensor housing 206″ includes anattachment pad 600 disposed on a bottom surface 252. The sensor housing206″ has a lower profile than previously disclosed embodiments.

FIG. 35 is a rear view of inserter assembly 200″ with attachment pad 600disposed on a bottom surface 252 of sensor housing 206″. It isunderstood that attachment pad 600 may be pre-installed on bottomsurface 252 of sensor housing 206″ or may be applied by the user priorto use of inserter deployment assembly 1000. Attachment pad 600 securessensor housing 206″ to the patient upon deployment of the continuousmonitoring system.

FIG. 36 shows a side, cross-sectional view of inserter assembly 200taken along line E-E of FIG. 34. Housing body 202 includes at least onefirst catch surface 210 defined by a recess 212′, opening, ledge,protrusion, or other structure. First catch surface 210 is constructedand sized to engage a corresponding resilient locking catch 214 (notshown) on deployment button 204 when a user presses deployment button204 into housing body 202 from a first or ready position (shown in FIG.10) to a second or insertion position (shown in FIG. 11). One or moresprings 216 (e.g., coil spring) disposed between deployment button 204and housing body 202 bias deployment button 204 towards the first orready position as shown in FIG. 36. Similarly as discussed above withreference to FIG. 10, when deployment button 204 is in the first (readyposition), locking catch 214 (shown in FIG. 10) is held inward intension by abutment with housing wall 218. When the user pressesdeployment button 204 down, the tension on locking catch 214 causeslocking catch 214 to move outward towards its resting,non-tensioned/non-compressed position to engage first catch surface 210.Of course, housing body 202 and deployment button 204 can be configuredso that first catch surface 210 is on deployment button 204 and lockingcatch 214 is on housing body 202. Other releasable locking mechanismsknown in the art are also acceptable. In one embodiment, inserterassembly 200 includes at least two first catch surfaces 210 andcorresponding locking catches 214 as shown in FIG. 10.

Deployment mechanism 208 is slidably received in a deployment mechanismcavity 228 in deployment button 204. A deployment cap 230 closesmechanism cavity 228 and can be removed for access to deploymentmechanism 208. Deployment mechanism 208 includes a deployment spring232, a needle/sharp carrier 234 with a needle carrier catch 235, and asensor deployment assembly 236′ with a resilient deployment catch 238.Deployment spring 232 (e.g., a coil spring) is disposed to engagebetween spring support component 231 and needle carrier 234 in atensioned orientation. Needle carrier catch 235 prevents needle carrier234 from being moved towards deployment cap 230 by deployment spring232. When the user presses deployment button 204 into housing body 202,needle carrier catch 235 is released by carrier release surface 203 ofhousing body 202 and deployment spring 232 then biases needle carrier234 towards a deployment cap 230.

FIG. 37 is an enlarged view of sensor deployment assembly 236′. Sensordeployment assembly 236′ includes a deployment body 236 a, a sensorcarrier 270, a sensor board 280′, and a needle bore 236 b that extendscompletely through sensor deployment assembly 236′. In this embodiment,the deployment guide 244 has been eliminated and a modified grommet 251′(shown in FIG. 36) has been incorporated to provide enhanced sealingbetween sensor carrier 270 and sensor housing 206″. As illustrated inFIG. 37, sensor 120 is bent so that the electrical contact portionhaving the plurality of contact pads is perpendicular to the electrodesand the deployment axis.

FIG. 38 is a rear, cross-sectional view of inserter assembly 200″. Asillustrated, locking mechanism 205′ is in its natural state of beinginwardly oriented and protrusion 205 a engaging a catch surface 206 a ofthe sensor housing 206″ to retain sensor housing 206″ to housing body202. As the deployment button is pushed down, a release surface 204 a ofside walls of the deployment button 204 engage the locking mechanism205′, 205 of the housing body 202 (see also FIG. 53D).

Turning now to FIG. 39, there is illustrated a sensor housing assembly800′. Sensor housing assembly 800′ is fully assembled after thesubcutaneous sensor 120 is implanted into a patient's skin and theelectronic cover assembly 850 is connected to the sensor housing 206″.Electronic cover assembly 850 includes a cover 852 with at least oneresilient cover locking tab 854 that secures cover 852 to sensor housing206″.

FIG. 40 illustrates a cross-section view of the sensor housing assembly800′ taken along line D-D of FIG. 39. As with the previous embodimentshown in FIG. 14, the sensor deployment assembly 236′ is retained withinsensor housing 206″. Sensor 120 extends through a grommet 251′ that issecured within a sensor opening 252 a in bottom surface 252 of sensorhousing 206″. The improvement in the structural configuration of grommet251′ along with a modification to the sensor carrier 270′ that providesbetter sealing between grommet 251′ and sensor carrier 270′, whichallows for the elimination of the deployment guide 244 illustrated inFIG. 14.

Cover 852 contains electronic module 700, which has a module circuitboard 702, a plurality of electronic components 704 that form theelectrical measurement circuit, and a battery 706 to power the circuit.The module circuit board 702 has a sensor deployment assembly portion710 that is oriented within cover 852 to extend over sensor deploymentassembly 236′ where sensor deployment assembly portion 710 has aplurality of electrical contacts/connectors that electrically couple themeasurement circuit to the respective electrical coupling pads 282′(shown in FIG. 41) of sensor circuit board 280′. When the electroniccover assembly 850 is assembled to sensor housing 206″, all of thesensor electrical connections are made between the electronic circuitboard 702 and the sensor circuit board 280′, including turning on thepower from battery 706 to the measurement circuit.

Turning now to FIG. 41, there is illustrated an exploded view of thecomponents of the sensor housing assembly 800′. In this embodiment,sensor housing assembly 800′ includes sensor housing 206″, a housingassembly gasket 802, sensor deployment assembly 236, electronic module700, and cover 852. Sensor housing 206″ includes a sensor deploymentassembly recess 211 a and an electronic module receiving recess 211 b.An assembly gasket 802 is positioned between a perimeter of sensorhousing 206″ and a perimeter of cover 852 to provide a seal against dustand moisture from entering into sensor housing assembly 800′. A grommet251′ is disposed at a bottom opening 252 a in bottom surface 252 ofsensor housing 206″ to provide a seal between sensor housing 206″ andsensor deployment assembly 236.

Sensor deployment assembly 236 includes deployment body 236 a, sensorcarrier 270′, sensor circuit board 280′, and sensor 120 coupled tosensor deployment body 236 a. Sensor deployment assembly 236 alsoincludes a needle bore 236 b through the entire assembly 236 into whichsensor 120 is disposed and from which sensor 120 extends. Sensor circuitboard 280′ has a plurality of electrically conductive electroniccoupling pads 282′, a plurality of electrically conductive sensorcoupling contacts 283′ and a plurality of electrically conductive powercoupling pads 284′. Power coupling pads 284′ close the measurementcircuit allowing electrical power from battery 706 to operate themeasurement circuit. Deployment body 236 a has a plurality of throughopenings 236 d in top surface 236 c to accommodate a plurality ofelectrical connectors 708 allowing the electrical connectors 708 toelectrically couple with the sensor circuit board 280′.

Electronic module 700 includes module circuit board 702 with sensordeployment assembly portion 710 that is oriented to extend over sensordeployment assembly 236′ where sensor deployment assembly portion 710has the plurality of electrical connectors 708 that electrically couplethe measurement circuit to the respective electrical coupling pads 282′,284′ of sensor circuit board 280′. Cover 852 captures assembly gasket802 between the perimeter of cover 852 and the perimeter of sensorhousing 206″ by the interlocking of resilient cover locking tab 854 witha mating sensor housing opening 206 c where a tab catch surface 854 a ismatingly captured by a corresponding retaining surface (not shown) insensor housing opening 206 c.

Turning now to FIG. 42, there is illustrated another embodiment of asensor housing assembly 800″. In this embodiment, a lumen 900 formedication delivery is incorporated within sensor deployment assembly236 (shown in FIG. 45). Cover 852 is modified to accept attachment of amedication delivery assembly 400′ or a cover plug (not shown). Cover 852includes a fluid receiving port 853 and at least one delivery assemblyretaining slot 860. Medication delivery assembly 400′ has a fluidcoupling stem 405 that is received into fluid receiving port 853 on oneend and to a flexible medication delivery tube 406 on an opposite end.Medication delivery assembly 400′ also has at least one resilient coverengagement tab 402 that matingly engages with the at least one deliveryassembly retaining slot 860 to capture and retain medication deliveryassembly 400′ onto cover 852. Medication delivery assembly 400′ mayoptionally include one or more alignment fingers 403 that slide intocorresponding finger receiver slots 870 on cover 852 to facilitatealignment and connection of fluid coupling stem 405 to fluid receivingport 853.

FIGS. 43 and 44 are views of sensor housing assembly 800″ showing sensorhousing 206″ with sensor deployment assembly 236 deployed within sensorhousing 206″ and electronic cover assembly 850 separated from sensorhousing 206″. FIG. 43 illustrates a top perspective view of the sensordeployment assembly 236 inside of sensor housing 206″ showing a largerneedle bore 236 b to accommodate a delivery bore stem 414 shown in FIG.44. Further and due to the inclusion of lumen 900 and medicationdelivery assembly 400′, the arrangement of one of the plurality ofthrough openings 236 in top surface 236 c of deployment body 236 a ismodified to accommodate insertion of delivery bore stem 414 into needlebore 236 b. The bottom perspective view of FIG. 44 shows the undersideof electronic cover assembly 850 and the location of electronic module700 and sensor deployment assembly portion 710 of module circuit board702. In this embodiment, a single lumen 973 is illustrated andrecognizable due to the sensor 120 extending from lumen 973. Lumen 973extends through sensor opening 250 in bottom surface 252 of sensorhousing 206″.

Turning now to FIG. 45, there is illustrated an exploded view of sensorhousing assembly 800″. Like FIG. 41, FIG. 45 shows the variouscomponents with the addition of lumen 972 and sealing member 412 withinneedle bore 236 b for sealing delivery bore stem within sensordeployment assembly 236. In addition, sensor deployment assembly portion710 has an electronic circuit board slot 711 to accommodate deliverybore stem 414 (shown in FIG. 44) therethrough.

FIG. 46 is an enlarged view of the electronic circuit board assembly 701of the electronic module 700. As can be seen, electronic circuit board702 has a plurality of electronic components 704 that form theelectrical measurement circuit for sensor 120. Also shown electricallycoupled on electronic circuit board 702 to the plurality of electroniccomponents 704 is radio antenna 724, which is used for transmitting datato a data receiver and display (not shown). Battery 706 provideselectrical power to the plurality of electronic components 704 and radioantenna 724. A sensor deployment assembly portion 710 of circuit board702 has a plurality of electrical connectors 708 and a circuit boardslot 711.

FIG. 47 illustrates an electronic module potted housing 720 from whichsensor deployment assembly portion 710 extends. Potted housing 720 is apotting material that encapsulates electronic circuit board assembly 701and battery 706 shown in FIG. 46. Potted housing 720 prevents a userfrom viewing and touching the plurality of electronic components 704 andradio antenna 724. Although reference number 722 appears to indicate aslot of sorts from which sensor deployment assembly portion 710 extends,it merely indicates the location in the potting material where theencapsulating material ends and the electronic circuit board continuesthat is not encapsulated. Electronic circuit board assembly 701, battery706 and potted housing 720 form electronic module 700.

FIGS. 48 and 49 illustrate a sensor housing assembly 800″ with a duallumen configuration. The notable difference between the structuralarrangement of the components in this embodiment compared to theembodiment for a single lumen shown in FIGS. 43-45 is the position ofthe electrical contact portion 124. Electrical contact portion 124 issituated between sensor circuit board 280′ and deployment body 236 awhereas in the single lumen embodiment of FIGS. 43-45, electricalcontact portion 124 is situated between sensor circuit board 280′ andsensor carrier 270′.

FIGS. 50 and 51 illustrate a cross-sectional view showing the relativeposition of the delivery bore 408 of the medication delivery assembly400′ to the components that form sensor deployment assembly 236 in thedual lumen embodiment. FIG. 51 is an enlarged view of the areadelineated by circular indicator H. Delivery bore 408 extends from fluidreceiving port 853 to delivery bore opening 408 a in delivery bore stem414. Delivery bore stem 414 fits into needle bore 236 b and againstsealing member 412. Sealing member 412 extends from deployment body 236a through sensor circuit board 280′ and into sensor/needle bore 272 ofsensor carrier 270′ providing a water-tight seal. Sensor carrier 270′includes a sensor bore 276 a that is transverse to sensor/needle bore272 and communicates with sensor board opening 285 that forms a portionof needle bore 236 b. Dual lumen 974 has first lumen tube 974 a alignedwith needle bore 236 b for sharp/needle 100 and a second lumen tube 974b for sensor 120. Second lumen tube 974 b communicates with sensor bore276 a. Sensor proximal portion 120 a of sensor 120 extends from secondlumen tube 974 b through sensor bore 276 a and sensor board opening 285,and then across a top sensor board surface 286 where the plurality ofcontact pads 121 electrically couple sensor coupling contacts 283′ ofsensor circuit board 280′.

There are several advantages of the various embodiments of the presentinvention. One aspect of the present invention provides an advantage fora nearly pain-free insertion of the sensor subcutaneously into the skinof a patient. Another aspect of the present invention provides theadvantage of a single action that implants the sensor 120, retracts theneedle/sharp 100, and releases the inserter assembly 200, 200′ leavingthe sensor housing 206, 206′, 206″ with the sensor 120 implanted wherethe sensor housing is ready for receiving the electronic module 300,700. In still another aspect of the present invention, it may include alumen 900 and a medication delivery assembly 400, 400′ to facilitatedelivery of medication in response to the sensor measurements of sensor120 in a single sensor housing assembly that is attached to the skin ofthe patient. In yet another aspect of the present invention, anotheradvantage is the inserter assembly design incorporates a further usefulfeature, which is the safe retraction of the sharp for safe disposal. Asharp is defined by the FDA (the US Food and Drug Administration) as adevice with sharp edges that can puncture or cut skin, and includesdevices such as needles, syringes, infusion sets and lancets. Improperdisposal or handling of sharps can cause accidental needle stickinjuries including transmission of Hepatitis B (HBV), Hepatitis C (HBC)and Human Immunodeficiency Virus (HIV). Used sharps must be placed in a“sharps” container such as the BD™ Home Sharps Container, and fullysealed, before checking with local laws on proper disposal.

The mechanism shown in FIGS. 12 and 33 show the sharp fully retractedinto the housing. The sharp is fully covered and is not accessible byfinger. By design, the device cannot be made to re-deploy the sharp. Nospecial “sharps” container is required to store and dispose of thehousing body after sensor deployment. The entire body can be disposed ofaccording to local laws.

For a better understanding and appreciation of the single action aspectof the present invention, FIGS. 52A-C and 53A-D provide a pictorialcross-sectional illustration in simplified form of this single actionaspect. Inserter assembly 200, 200′ in FIGS. 52A-C represent the presentinvention in the ready-to-use position; that is, the assembly is readyfor installing a continuous analyte monitoring system on a patient. FIG.52A shows a cross-sectional view of deployment button 204 in a readyposition where the resilient locking catch 214 is tensioned inwardly bythe wall 218 of housing body 202. Spring 216 tensions deployment button204 upwardly while resilient locking catch 214 prevents deploymentbutton 204 from being separated from housing body 202 by spring 216.FIG. 52B shows a different cross-sectional view of deployment mechanism208 being tensioned by deployment spring 232 where the needle carriercatch 235 prevents any upward movement of deployment mechanism 208 bydeployment spring 232. FIG. 52C shows still a different cross-sectionalview of housing body 202 where resilient locking mechanism 205 engagessensor housing 206, 206′, 206″ and retains the sensor housing to theinserter assembly 200, 200′.

FIGS. 53A-D represent the substantially simultaneous single action ofthe present invention where the needle 100 implants the sensor 120, theneedle 100 retracts, the deployment button 204 gets into a lockedposition, and the inserter assembly 200, 200′ releases from the sensorhousing 206, 206′, 206″. The single action involves simply depressingthe deployment button 204. FIG. 53A shows a cross-sectional view of thedeployment button 204 in a second, locked position where the resilientlocking catch 214 locks into recess 212 of housing 202 when resilientlocking catch 214 transforms from the tensioned position to the relaxedposition. Substantially simultaneously as the deployment button 204reaches the second position as FIG. 53B shows in a differentcross-sectional view, needle carrier catch 235 contacts carrier releasesurface 203 and is tensioned towards needle carrier 234 causing carriercatch 235 to disengage from button catch surface 240. As carrier catch235 disengages from button catch surface 240, sensor deployment assembly236 is positioned within sensor housing 206 and deployment body catch238 engages base catch surface 242. FIG. 53C is the same cross-sectionalview as in FIG. 53B. FIG. 53C shows needle carrier 234 at an upper endof deployment button 204 and being pushed to that position by spring 232as spring 232 expands from its tensioned position to a relaxed positionwhen needle carrier catch 235 is released from carrier release surface203. FIG. 53D shows still a different cross-sectional view of inserterassembly 200, 200′ where resilient locking mechanism 205 of housing body202 is pushed outwardly away from sensor housing 206, 206′, 206″ byprotrusion 205 a releasing catch surface 206 a, which occurs whendeployment button 204 arrives at the second, locked position. Thiseffectively releases the inserter assembly 200, 200′ from sensor housing206, 206′, 206″ caused by release surface 204 a of the deployment button204 engaging the locking mechanism 205′, 205 of the housing body 202. Itshould be appreciated that, when a user performs this single actionafter placement on the skin of the patient, the substantiallysimultaneous occurrence of the locking and releasing of the variouscatch surface produces a single, audible sound such as, for example, aclick, as well as providing a single sensory vibration in the inserterassembly. The audible sound and the sensory vibration also occursubstantially simultaneously. This alerts the user that the needle 100has implanted sensor 120, that the needle 100 has already retracted intothe inserter assembly 200, 200′, that the inserter assembly 200, 200′has been released from sensor housing 206, 206′, 206″, and the sensorhousing with the sensor 120 remains on the skin of the patient where thesensor housing is ready for receiving the electronic module 300, 700 ifit was not already coupled to the sensor housing.

As stated previously, the inserter assembly design incorporates afurther useful feature of the present invention, which is the saferetraction of the sharp for safe disposal. A sharp is defined by the FDA(the US Food and Drug Administration) as a device with sharp edges thatcan puncture or cut skin, and includes devices such as needles,syringes, infusion sets and lancets. Improper disposal or handling ofsharps can cause accidental needle stick injuries including transmissionof Hepatitis B (HBV), Hepatitis C (HBC) and Human Immunodeficiency Virus(HIV). Used sharps must be placed in a “sharps” container such as theBD™ Home Sharps Container, and fully sealed, before checking with locallaws on proper disposal.

The mechanism shown in FIGS. 12 and 33 show the sharp fully retractedinto the housing. The sharp is fully covered and is not accessible byfinger. By design, the device cannot be made to re-deploy the sharp. Nospecial “sharps” container is required to store and dispose of thehousing body after sensor deployment. The entire body can be disposed ofaccording to local laws.

Referring now to FIG. 54, a flow chart illustrates exemplary steps of amethod 500′ for continuous analyte measurement such as, for example,glucose with or without optional periodic medication delivery. To start,at step 502 select one of an inserter assembly 200, 200′, 200″ thatcontains either a sensor deployment assembly 236 with a sensor 120 andwithout a lumen 900 at step 503 or a sensor deployment assembly 236 witha sensor 120 and a lumen 900 at step 504. At step 505, select aninserter assembly 200, 200′, 200″ having either a sensor housing 206,206′, 206″ unassembled with an electronic module 300, 300′ or a sensorhousing 206, 206′ pre-assembled with an electronic module 300, 300′. Atstep 510, optionally place a sensor housing adhesive pad 600 configuredfor use with sensor housing 206, 206′, 206″ onto the bottom of thesensor housing. It is contemplated that adhesive pad 600 may already beattached to the inserter assembly where the user simply remove a backingfor attaching the inserter assembly to a user's skin. It is furthercontemplated that other modes of adhesively securing the sensor housing206′ to the patient may be used, all as is well known in the art.

At step 520, inserter assembly 200′ is placed on the insertion site ofthe patient with sensor housing 206′ and, if optionally attached, sensorhousing adhesive pad 600 contacting the patient's skin. In oneembodiment, the area of contact is quite small, measuring about 1 inch(25.4 mm) wide by about 1.5 inches (38.1 mm) long. In one embodiment,step 520 includes fixing inserter assembly 200, 200′, 200″ to the skinusing medical grade adhesive tape or the like.

At step 525, the user manually presses button 204 down to its secondposition (down position) to drive the low-force needle/sharp 100,continuous monitoring sensor 120 and optional lumen 900, as the case maybe. Typically, the needle/sharp 100 is inserted about 8 mm into thesubcutaneous tissue. Step 525 has been shown to take about 0.1 lbs. offorce and be virtually painless to the patient.

At step 530, deployment mechanism 208 “bottoms out” or reaches itsfurthest downward position towards sensor housing 206, 206′, 206″. Anaudible “click” along with a sensory vibration alerts the user. At step535, the audible click and the sensory vibration indicates to the userthat the sensor 120 has been implanted, needle/sharp 100 has retractedback into inserter assembly 200, and inserter assembly 200 has releasedfrom sensor housing 206, 206′, 206″.

During step 535, deployment mechanism 208 automatically retracts ormoves from the second carrier position (down position) to a thirdcarrier position (up position), leaving continuous monitoring sensor 120and optional lumen 900 inserted about 7 mm from the surface of the skin.Needle/sharp 100 is released by the double acting deployment mechanism208 that quickly retracts needle/sharp 100 and sharp carrier 234.

At step 540, housing body 202, deployment button 204, and deploymentmechanism 208 (also collectively referred to as the inserter assembly200) are removed from sensor housing 206, 206′, 206″ without requiringany further action to be performed to cause the inserter assembly 200 torelease from the sensor housing. As previously described, release ofinserter assembly 200 from the sensor housing occurs automatically asdeployment button 204 “bottoms out” and causes the release of lockingmechanism 205 (e.g., pressing a snap feature) on housing body 202 awayfrom sensor housing 206, 206′, 206″. The sensor housing is left on thepatient. It is noted that manually pressing button 204 down to itssecond position (down position), which simultaneously moves deploymentmechanism 208 and sensor deployment assembly 236, causes movement ofdeployment button 204, deployment mechanism 208 and sensor deploymentassembly 236 to occur in the same linear and parallel direction.

If the inserter assembly 200 selected at step 505 was one pre-assembledwith the electronic module, then electronic module 300, 300′ is turnedon at step 550 by any number of possible mechanisms such as, forexample, a switch or removal of a non-electrically conducting substratebetween electrical contacts, and the like. If the selected inserterassembly 200 was one without a lumen 900 at step 556, then the installin complete at step 565. If, however, the selected inserter assembly 200was one with a lumen 900, then the medication delivery assembly 400,400′ is attached to the sensor housing, which then completes the installat step 565.

If the inserter assembly 200 selected at step 505 was an un-assembledwith the electronic module, then the electronic module 300, 300′ isinstalled in the sensor housing 206, 206′, 206″ at step 545. If theselected inserter assembly 200 was one without a lumen 900 at step 556,then the install in complete at step 565. If, however, the selectedinserter assembly 200 was one with a lumen 900, then the medicationdelivery assembly 400, 400′ is attached to the sensor housing, whichthen completes the install at step 565. It is understood that themedication delivery assembly 400, 400′ is releasably connected to theneedle bore 272 of sensor deployment assembly 236 creating a water-tightseal with a sealing member 412 between a delivery bore 408 and needlebore 272. Delivery tube 406 is connected between delivery bore 408 and amedication delivery module that contains, for example, insulin when thesensor is a glucose sensor.

At step 565, the completed sensor housing assembly is now operational.Whether the electronic module 300, 300′, 700 is turned on automaticallywhen the electronic module is assembled to the sensor housing or ismanually switched on, the electronic module begins receiving electricalsignals generated by sensor 120. The electrical signals generated bysensor 120 that is implanted subcutaneously in a patient are directlyrelated to the analyte concentration in the subcutaneous tissue. In thecase of where a glucose sensor is used, the electrical signals generateby sensor assembly 135 are directly related to the glucose concentrationin the subcutaneous tissue. Electronic module 300′ contains theelectronic and/or electrical components that allows for measuring andrecording the analyte of interest, which in the case of continuousglucose monitoring, is glucose. The data obtained from sensor 120 may bestored in electronic circuitry of the electronic and/or electricalcomponents in electronic module 300, 300′, 700 for simultaneous or laterdisplays and/or transmission of the generated data. The electronicmodule may also include an inductive charging capability so that theonboard battery source can be conveniently charged without removal fromthe sensor housing.

Although the preferred embodiments of the present invention have beendescribed herein, the above description is merely illustrative. Furthermodification of the invention herein disclosed will occur to thoseskilled in the respective arts and all such modifications are deemed tobe within the scope of the invention as defined by the appended claims.

What is claimed is:
 1. An inserter assembly for implanting a sensorsubcutaneously into a patient, the assembly comprising: a housing bodyhaving a first body end and a second body end; a deployment button atleast partially disposed in and slidable within the housing body throughthe first body end, the deployment button being movable from a firstposition to a second locked position; a deployment mechanism slidablydisposed within and with respect to the deployment button, thedeployment mechanism being movable, within and with respect to thedeployment button, between: a ready position, an insertion position, anda retracted position, and the deployment mechanism having a needle; asensor deployment assembly disposed within the housing body andremovably mated with the deployment mechanism, the sensor deploymentassembly having a needle bore in which the needle is disposed when thedeployment mechanism is in the ready position, and a sensor partiallydisposed within the needle bore, wherein the deployment mechanism, theneedle, and the sensor define a deployment axis, the sensor having anelectrical contact portion wherein the electrical contact portion isbent perpendicularly relative to electrodes and the deployment axis; anda sensor housing disposed at and removably retained by the second bodyend of the housing body, the sensor housing having a bottom surface anddefining a sensor opening therethrough that is aligned with thedeployment axis, wherein movement of the deployment button from thefirst position to the second locked position causes the sensor to beimplanted subcutaneously into the patient along the deployment axis, theneedle of the deployment mechanism to retract to the retracted position,the sensor deployment assembly to be fixed within the sensor housing,and the housing body, the deployment button and the deployment mechanismto release from the sensor housing.
 2. The apparatus of claim 1, whereinthe sensor deployment assembly comprises: a sensor deployment body witha sensor deployment locking mechanism configured to engage the sensorhousing when the button is moved to the second locked position, therebylocking the sensor deployment assembly with the sensor housing; a sensordeployment guide attached to the sensor deployment body and positionedto abut the sensor housing to stop travel of the sensor deploymentassembly when the deployment button is moved to the second lockedposition; a sensor carrier attached to the sensor deployment guide andsecuring the sensor, the sensor carrier having a board-receiving face ona top sensor carrier surface and extending transversely to thedeployment axis; and a sensor board mated with the board-receiving faceand having a plurality of electronic coupling pads positioned for beingelectrically coupled to measuring electronics, wherein the sensorextends through the sensor bore and along the sensor board with theelectrical contact portion of the sensor electrically coupled to theplurality of electronic coupling pads.
 3. The apparatus of claim 1,wherein the deployment axis is substantially perpendicular to the bottomsurface of the sensor housing.
 4. The apparatus of claim 1, wherein thebottom surface of the sensor housing is configured to contact thepatient during implantation of the sensor.
 5. The apparatus of claim 1,wherein the sensor implanted subcutaneously in the patient has a workingelectrode of an electrode system on the sensor extending into thepatient by about 4 mm to about 7 mm.
 6. The apparatus of claim 1,wherein the sensor implanted subcutaneously in the patient has a workingelectrode of an electrode system on the sensor extending into thepatient by about 2 mm to about 10 mm.
 7. The apparatus of claim 2,wherein the sensor deployment locking mechanism comprises one or moreresilient deployment catch on the sensor deployment assembly biased toengage a deployment catch surface on the sensor housing.
 8. Theapparatus of claim 1 further comprising: a resilient button catch on oneof the housing body or the sensor housing, the button catch biased toengage a button catch surface on the other of the housing body or thesensor housing when the deployment button is in the second lockedposition; a resilient needle-carrier catch on one of the deploymentbutton or the needle carrier, the needle-carrier catch biased todisengage a second catch surface on the other of the deployment buttonor the needle carrier when the deployment button is moved to the secondlocked position; and a resilient housing catch on one of the housingbody or the sensor housing, the housing catch biased to disengage ahousing catch surface on the other of the housing body or the sensorhousing when the button is moved to the second locked position.
 9. Theapparatus of claim 1, wherein the movement of the deployment button fromthe first position to the second locked position is a single movementcausing substantially at the same time the sensor to be implantedsubcutaneously into the patient along the deployment axis, the needle ofthe deployment mechanism to retract to the retracted position, thesensor deployment assembly to be fixed within the sensor housing, andthe housing body, the deployment button and the deployment mechanism torelease from the sensor housing.